[Asterisk-Users] Asterisk Indications

[Steve Underwood]

Christopher Lee wrote:

>>On Sun, 25 Jan 2004, Steve Underwood wrote:
>>    
>>
>>>Actually, nothing would use a 17Hz tone - it doesn't pass through a
>>>300-3400Hz channel very well :-)
>>>      
>>>
>>It's not a 17Hz tone.  Australian (and others) tones are single-frequency
>>tones that are amplitude-modulated at a second, much lower, frequency.
>>The "x*y" notation in indications.conf is supposed to reflect this: for
>>example, 400*17 would be a 400Hz tone amplitude-modulated at 17Hz.
>>    
>>
Its generally better to read the message you are replying to, before 
making a meaningless reply :-)

>
>So does that mean the second frequency is 400-17 = 383Hz ? I've tried
>400+383, but it didn't sound right.
>  
>
If you amplitude modulate, or multiply, you loose the original tone, and 
end up with two tones at the sum and the difference of the two tones you 
are using. Thus 400*17 gives 383+417.

>>I posted a few days ago that nothing seems to happen when I specify the
>>modulation frequency in my indications.conf -- all I get is the constant
>>400Hz tone.  I will try some of the other combinations mentioned and see
>>if they produce something more suitable.
>>    
>>
>
>I've now settled on my ring tone as being 400+425.
>  
>
Could be right. As I said, some ITU documentation I checked says 
Australia uses 400*17, but that is over 10 years old. Maybe things have 
been changing. 400 + 425 and 400 + 450 are more common combinations 
around the world these days.

Regards,
Steve